Branchburg municipal solar project expands to include carport panels

The $2 million solar energy project under way at the municipal building will be expanded to include a $400,000 element that would draw energy from panels set on carports in the north parking lot of the building.

BRANCHBURG — An 11-year difference in how quickly the township can expect a return on its investment was a principle factor in the decision to add photovoltaic panels on carport roofs to a solar energy project already under way at the municipal complex.

The Township Committee agreed on Dec. 12 to install carports topped with a 50 kw solar array in the north parking lot of the municipal building rather than retrofit the roof of the Department of Public Works garage with a 22 kw system.

According to Township Administrator Gregory Bonin, both projects had approximately the same price tag, about $400,000, favoring the project with the greater electrical output, and the rooftop panels would have required reinforcing the garage roof.

Moreover, the time it would take for the township to recoup its investment would have been 17 years — compared with a six-year span for the carport project, Bonin said.

Those estimates were partially based on the amount of revenues the township expects from the annual sale of solar renewable energy credits to energy companies so those companies can meet the state’s annual solar energy standards.

The fluctuation in the value of SRECs makes it tricky to predict the return on investment time table.

Currently, SRECs are trading at about half their 2010 value.

Bonin said that the carports would not entirely cover the north parking area and would be high enough from the ground to accommodate large vehicles. According to Paul Witwick of Triad Consulting Engineers, the township’s consultant on the projects, nearby Raritan Valley Community College and Ortho Pharmaceuticals have similar carport solar arrays.

A $2 million solar project — to put a 280 kw system of photovoltaic panels on the roof of the municipal building and on the roof of the police headquarters — is already under way. As with the $400,000 carport project, half of the money for the larger project is from a federal grant. The township foots the bill for the balance.

If all the energy from the two projects were to power just the municipal building, the township would not need to purchase any electricity for the building, Bonin said. In actual practice, the electricity from the solar arrays will be fed to both the municipal building and police headquarters. The combined solar output is expected to meet about 60%-65% of the energy needs of both buildings.

Construction of the first project is expected to be complete sometime this spring, Bonin said. The Township Committee will probably seek to expand its agreement with Triad to include the design of the carport project and that construction could begin about the time that solar energy begins to flow from the original project, he said.

The township has also applied for an additional $100,000 federal grant to purchase electric vehicles and install electric charging stations.